Retaining valve



Sept. 7 1926. I 1,599,206

C. A. CAMPBELL ET AL i RETAINING VALVE Filed Oct. l, 1925 1759-1- L A v2 I A ll l i Q 3 g 29 a7 n Z `7 1| u1 Q z2 f Y. //.I//// JZ- f-V 73 6 J7 Z5 v 6 J0 a 1119 .Z8

Ey @dy/@JQ Patented Sept. 7, 1926.

' UNITED." STATES PATIENT CHARLES A. CAMPBELL Ann Env/1N C. vinci-ann, onufnrnnfrown; NEW YORK',v .Asfr SIGNCns To THE NEW Yoan Ain Venana COMPANY. A CCRQPCRATICNYCF NEW'- JERSEY.

RETAINING VALVE;

applicati@ inea 'october 1o, 1925. serirno 61,746;

This invention relates to pressure relief valves and particularly to retaining valves for air brakes.

vAs iswell understood in the air brake art, a retaining valveis a loaded valve Which is applied to the exhaust port of the brake cylinder and which may be set in eitherv an operative orV` an inoperative position. inoperative lposition ity oiersa, free exhaust f to the atmosphere. This is the normal position. In the operative position the valve functions `toimaintain a definite pressure in the brake cylinder. The retaining valves are set to this second position manually on long grades to hold pressure on the brake cylinders While the engineer recharges the reservoirs, since release is normally simultaneous With recharge.

The usual spring loaded retaining valve it used to retain lon7V pressure opens and closes sluggishly andis apt to beheld partly openby small particles of grit-or scales The object ofthe present invention is to produce a muchmore refined type of valve Which -Will open and close'quickly,' which can be relied upon to seat tightly when ity closes, `and lWhichrequires little orV no maintenance care. v 1 v To accomplishthis result, theV valvefseat ismade in thel orm'of a narrow annular rib and the valve is ay flexible metallic dia` phragm.- The valve seat is of such size relatively to the total area of `the diaphragm that When the valve opens there is -a considerably increased area of diaphragm subject to the pressure of the'discharging air. This pressure is rendered effective by a restricted exhaust -port vin the vent passage beyond the valve. As soonas the valve starts to open, the restriction; causes back vpressure `to buildv up on the diaphragm and this, with the increased area exposed, causesim'rnediate Wide opening ofthe valve;y Inthe closingaction, as soonl as*the'throttling'actionbetween the valve. andthe Seat exceeds' .the .throttling action: of the vent port,1the valve closes sharp. lyybecausethen theivalve port-z acts toY bleed away apart-of the pressure-eective Vto hold thevalveaopenz. 1

`The .preferred Figl; I Fig. 3 is a fragmentarysection siinilar to In the a portion of Fig. 1 and showing the-control @abonnementen invern tionV is?V illustrated in' the."V accompanying 1- isa' View partly elevation partly in section'on the line ofy In this view the kcontrol cock is'iiiits normal tainingfvalve iscutoif; VFig. 21s a section onthe line 2 2 of cock in positioirto directthebrale cylinder` exhaust throughthe,retainingvalve.

The vbody of thevalve casingis shotvnat 6 and is provided With perforated ears?l by means of Which it may be attached. H\l`. h e .r e mainder of the2 valve casingponsists L of a bonnet Sthreaded inthe top of the' body .H6

and al cap 9 threadedintofthe top of the bonnety 8. 1

' positionQin which theeXhaust passage 1sl connected direct to atmosphere and the re` At the lowerendof` isy threaded `fitting1l 1 0 to which V.the exhaust pipe from the brake cylinder (not:.sh xyn.)f is connected This leadsto aport 11..: Comi? munication romntlie port; 11 j1to a continu- 1 ation. port 12 is controlledby a plug' .cock

18 'which is provided with a' ,f gfroolvejl.port

extending somewhat more thanhaltivay around its periphery. In oneposition ot the plug 13 (that shovvnin Fig. 3) the port 14 connects theports 11 an d 12, thus putting the retaining'. valve into action. the other position of the' cock V1 3, the j port. 11l connects theV port 11 with theexhaust portt 15. This position isshownin Figs: ltand 2 andV is the normal position of .thefdevice, the retainingfvalve beingthen out-of action.

AThe .cocl 13 is of usual construction, .be-l

ing seated by af spring. lconnedby. a threaded cap 17. {Thevalve is rotated 'by means ofva vhandle 1'8 which svvngsjbet'ween' limitinglpositions defined by'stops 1 9and 20 L The port 12 leads to avalve-chaniber 2 1. in l which is mounted' an` annular .seat ymember r22 formed'with anupstanding f rib 23 Vwhich serves .as the valve/seat.. vThe seat` member, 22j is renewable; and` isaprovided withr a valve;- prt. Qlaedna 1`0H1-ts- .center to. :the: atmosphere through .we ,Choke -.01 .refstriction `forniedinl a' member1 25. which; is

riby ontlie seat. member 2 2; is a metallic scf ` body 6 at 28 and thus serves as a threaded clamping member for the ring 27 and diaphragm 26.

A thrust member 29 is mounted within Vthe clamp ring 2'? so as to contact with the entire face of the diaphragm within the ring. The thrust member 29 is formed with an upwardly extending flange 30 which slides in a guideway in the bonnet 8. The parts are so arranged that the thrust member 29 is confined so that it has-a simple straight line sliding mot-ion quite limited in extent, but suiicient to permit the diaphragm to flex under pressure in the chamber 21 and move away from the seat rib The clamp ring 27 is recessed on its lower face with a convex curvature designed to imparta gradual liexure curve to the dia'- phragm. It is preferred to make the two opposed surfaces of the ring 27 alike so that it may be reversed, but this obviously is not essential.

The thrust member 29 is urged downward by a spring 81 which seats against the member 29 at one end within the flange 30 and which is confined at its other end by the cap 9. As stated, the cap 9 is threaded into the bonnet 8 and henc-e is removable to permit an interchange ot' springs. The space'above the diaphragm 26 is vented to the atmosphere and this is conveniently accomplished by a vent port 32 which is shown as formed in the bonnet. It obviously might be otherwise located.

Vh-en the cock 13 is in the position shown in Fig. 1, the retaining` valve is cut out and the brake cylinder exhausts normally to the atmosphere through the port 15. y When the cock 13 is in the position shown in Fig. 3, the port 15 is closed `and th-e exhaust is directed through the ports 11 and 12rto the valve chamber 21.

It the pressure in the chamber 21 is inadequate when acting on the diaphragm outside ot' the seat rib 23 to overpower the spring 31, the valverremains closed. If the brake cylinder pressure is greater, however, the 'diaphragm 26 will move up, allowing flow to start through port 24 to choke 25. If this flow is greater than the capacity of choke 2,5, backy pressure will build up in the port 24 .and the entire area of diaphragm 26 becomes effective, thus causing' the valve to open wide. As the brake cylinder pressure gradually falls, the ldiaphragm 26 will approach the seat rib 23 gradually and ultimately a position' will -be reached when the throttling between the diaphragm and the seat rib exceeds the throttling in the choke 25. When this occurs, the pressure onthat area of the 'diaphragm included, within the seat rib will drop quite4 rapidly and consequently the spring 31 will quickly overpower the diaphragm and seat it upon the rib 23.

This quick opening and quick seating characteristic is important because it gives prompt venting of the brake cylinders to the desired retained pressureandbecause it ensures tight seating of the retaining valve. The valve seat rib has a narrow edge, vso that small particles of' scale or dust have almost no opportunity to become lodged on the seat. rlhis fact, coupled with the flexibility of the diaphragm, ensures tight seating without undue maintenance care.

lVhile the arrangement illustrated is preferred, it is obvious that changes may be made from the specific embodiment' shown without sacrifice of the advantages enumerated and consequently no limitation to the specific structure shown is intended except to the extent specified in the claims.

What is claimed i-s: Y

l. In a retaining valve, the combination ot' an annular' valve seat; a flexible diaphragm valve coacting therewith and having a total effective area larger than the area included within the margins of said valve seat; resilient means urging said diaphragm toward said seat; and flow restricting means'located on the discharge side of said valve and arranged to restrict the outliow through the valve to an amount less than the maximum capacity of the valve.

2.. ln a retaining valve, the combination ot' a valve seat comprising a narrow annular rib; a flexible diaphragm valve adapt-Y red to seat against said rib and having an eliiective area materially great-er than the area included within said rib; resilient means urging said diaphragm toward said seat; fand flow restricting means locatedY on the discharge sid-e of said valve and arranged to restrict the outflow through the valve t0 an amount less than the maximum capacity of the valve. A

3. In a retaining valve, the combination of a body formed with a retaining valve chamber, an atmospheric port, and a port for connection with the exhaust port ofl a brake cylinder; a cock shiftable between two positions, in one of which it connects the last-named connection with said atmospheric port, and in the other of which it closes said atmospheric port and connects said connection with said retaining valve chamber; ya. narrow annular rib in .said chamber serving as a valve seat; a metallic diaphragm of greater diameter than said valve seat, said( diaphragm being` also mounted in said chamber and .subject to the pressure therein a spring urging said diaphragm into contact with said rib; and means for affording a restricted flow of fluid from lsaid valve seat within ysaidV rib, the rate-of such restricted How being less than the maximum flow capacity between the seat and the diaphragm.

Y 4. In e brake retainer, the combination 5 of a loaded valve .subject in en opening direction to the pressure of brake cylinder exhaust, nd arranged to present an increased effective area to such pressure in an 0Qenidg direction when open; and a constriction in the ioW path beyond said valve, said con- 10 striction. serving to throttle the flow to L rete less than the maximum capacit-y otsaii valve. 'c In testimony whereof We have signed our names to this specification.

CHARLES A. CAMPBELL. nRWrN o. Vnoivnin 

